System Memory - Compaq Deskpro 4000 Technical Reference Manual

Chapter 3 Processor/Memory Subsystem
3.2.2

SYSTEM MEMORY

The system board contains three 168-pin DIMM sockets for system memory. This system is
designed for using SDRAM DIMMs. As shipped from the factory the standard configuration may
be 32 or 64 megabytes installed. The addition of 8-, 16-, or 32-, 64-, or 128-MB DIMMs allows
the expansion of system memory up to a maximum of 384 megabytes. Single or double-sided
DIMMs may be used. Parity is not implemented in this system.
The system memory uses the following RAS line assignments:
The performance times of the SDRAM is listed as follows:
Table 3–4. SDRAM Performance Times
Parameter
Burst Read Page Hit:
Read Row Miss
Read Page Miss
Bk-to-Bk Burst Reads
(Pg Hit )
Write Page Hit
Write Row Miss
Write Page Miss
Posted Write
Write Retire Rate from
Posted Write Buffer
SLD = Speculative Lead Disable
3-6 Compaq Deskpro 4000 and 6000 Personal Computers
featuring the Pentium II Processor
RAS#0 DIMM 1, Bank A
RAS#1 DIMM 1, Bank B
RAS#2 DIMM 2, Bank A
RAS#3 DIMM 2, Bank B
RAS#4 DIMM 3, Bank A
RAS#5 DIMM 3, Bank B
Table 3-4.
SDRAM Performance Times
CAS Latency = 3 CLKs
10-1-1-1
10-1-1-1
13-1-1-1
9-1-1-1, 1-1-1-1 (SLD=0, SSRE = 1)
10-1-1-1, 1-1-1-1 (SLD=0, SSRE = 1)
SSRE = SDRAM Speculative Read Enable
First Edition - October 1997
9-1-1-1
8-1-1-1, 2-1-1-1 (SLD=0, SSRE=1)
9-1-1-1, 2-1-1-1 (SLD=0, SSRE=1)
3
6
9
3-1-1-1
-1-1-1
CAS Latency = 2 CLKs
8-1-1-1
9-1-1-1
10-1-1-1
10-1-1-1
3
6
9
3-1-1-1
-1-1-1